Description ADULT SUMMER Has dark gray upperparts and paler gray underparts including neck. Head is white, bill is proportionately long and red with dark tip, and legs are dark. In flight, note white trailing edge to otherwise dark wings (above and below), and white-tipped, dark tail feathers that contrast with pale rump. ADULT WINTER Similar, but head and neck are streaked and grubby-looking. JUVENILE Juvenile and firstwinter birds are dark brown with dark legs and dark-tipped, dull pink bill. Adult plumage is acquired gradually by successive molts over subsequent 3 years.

Dimensions Length: 18-21" (46-53 cm)

Habitat Breeds off western coast of Mexico (Feb-May); vast majority nest on Isla Raza in Gulf of California. Post-breeding birds move north along Pacific coast, and are common as far north as Vancouver Island Jul-Oct; thereafter range contracts south in fall and southern California is northernmost limit of winter range. Outside breeding season, favors sandy beaches, sometimes congregating in vicinity of river mouths.

Observation Tips Easy to see on many sandy beaches in California, Jul-Feb.

Range Western Canada, Southwest, Northwest, California

Voice Utters a harsh krrrh call.

Discussion Striking and distinctive, long-bodied and long-winged gull. Adult has unique combination (for a gull) of dark body and white head; takes 4 years to acquire adult plumage. Juvenile and first-year birds are dark brown and could be confused with immature jaegers or skuas; note, however, Heermann's lack of pale crescent at base of primaries, seen in those species. Sexes are similar.